Visual display systems for providing an aircraft pilot terrain situational awareness and real-time, dynamic display of any terrain hazards are generally well-known. Typically, such displays show terrain and potential hazards formatted in either a horizontal terrain elevation view or a profile terrain elevation view relative to the host aircraft's position, altitude and heading.
FIG. 1 shows a known terrain situation awareness display 10 that illustrates by example on the upper portion a horizontal or plan terrain elevation view 12, also known as a “bird's eye” or map view, and on the lower portion a profile terrain elevation view 14, as described by Wichgers, et al. in U.S. Pat. No. 5,936,552, INTEGRATED HORIZONTAL AND PROFILE TERRAIN DISPLAY FORMAT FOR SITUATIONAL AWARENESS, which is incorporated herein by reference in its entirety. Both views are based on a display generated using a Jeppesen supplied database that covers a 300 by 270 mile area of terrain. Scale of the display 10 is indicated by numerals thereon. For example, when the scale of display is a total of 160 miles ahead of the aircraft (triangle icon 16) to the top of the screen, the numeral “80” is shown in the center of horizontal elevation view 12 to indicate the midpoint. The numerals “1,” “80,” and “160” similarly show the scale at the bottom of profile view 14. The display format scaling is selectable similar to weather radar display scale selections, or is continuously selectable.
The horizontal elevation view 12 uses a triangle icon 16 to indicate the host aircraft's current position. Current aircraft altitude 18 is depicted on the horizontal elevation view 12 as an altitude of 4200 feet above Mean Sea Level (MSL). Aircraft heading is indicated by the vertical dashed line 20 extending from triangle icon 16 to compass rose 22 and the selected aircraft heading is 357 degrees as indicated by the triangular heading bug 24 on the compass rose 22.
The horizontal elevation view 12 displays elevation data for the region around the aircraft, the terrain elevation data is supplied by a database as a function of aircraft position. Terrain elevations are displayed relative to the aircraft, rather than absolute elevations. Terrain elevations higher than a pre-selected “comfort zone” below the current aircraft altitude are depicted by illuminating corresponding pixels of the display. See, for example, regions 26 of display 10. The display is monochromatic for terrain elevations below the pre-selected comfort zone.
The profile situational awareness display portion 14 of the display 10 indicates the aircraft present position using triangle symbol 28. Horizontal dashed line 30 represents current aircraft altitude and is useful for determining terrain clearance. Terrain profile 32 depicts the vertical terrain elevation profile of the path directly in front of the aircraft as supplied by the database of terrain elevation data as a function of aircraft position. The terrain profile 32 of the profile display 14 depicts a section view or “slice” of terrain elevation information taken along the aircraft heading, as indicated by vertical dashed line 20 of the horizontal elevation view 12.
The display 10 is color coded (colors not shown) according to terrain elevations relative to the aircraft. For example, the colors red, yellow, and green are used to indicate warning, caution, and all clear, respectively. Accordingly, horizontal elevation view 12 are shown using the color red (not shown), indicating warning, to display all terrain elevations which are higher than the host aircraft's current altitude.
The same color scheme (not shown) is used in profile view 14 to display all portions of the flight profile 32 which are higher than the current altitude as indicated by dashed line 30.
The color yellow (not shown), indicating caution, is used to display terrain that is below the aircraft's current altitude but higher than the selected comfort zone. Those portions of horizontal elevation view 12 and profile view 14 are accordingly displayed in yellow.
The color green (not shown), indicating “all clear,” is used to display terrain below the selected comfort zone and is not currently a hazard to the aircraft. Blue (not shown) is used to display large bodies of water. Other colors or symbology are utilized to indicate other database information on the display, such as restricted airspace and airport locations.
By providing detailed data only for terrain elevations above the selected comfort zone, such systems fail to supply information about terrain that is not at present a potential threat. Except for color coding large bodies of water and specific database information, such as restricted airspace and airport locations, details are eliminated below the selected comfort zone elevation, and the terrain is painted a single safe or “all clear” color. Known terrain situational awareness display systems are thus limited to displaying only tactical information to which the pilot must react in the short term.